Fresh water dispensers are nowadays common in work offices and public building of America and Europe. They are preferred by some to the municipal tap water because of health safety considerations relating to concerns as to the quality control thereof.
Indeed, an increasing number of persons are worried about pollution of underground bodies of water from uncontrolled release in the biota of dangerous chemical compounds by unscrupulous individuals. It is noted that rainwater will bias ground level dry chemicals to seep as a liquid solution through the soil, to eventually reach and contaminate the underground bodies of water--a process known as lixiviation. Lixiviation is particularly a problem in uncontrolled dumps that do not include an underlying waterproof base sheet, that would otherwise receive, support and contain solid and liquid wastes on the ground, as is currently required by municipal regulations in authorized dumps.
In these known water dispensers, a large transparent semi-flexible wall water bottle is provided in inverted condition atop the dispenser frame, to gravity-feed the water to an intermediate water reservoir inside the dispenser frame, before controlled escape through the underlying dispenser outlet nozzle. The water bottle size ranges between 1 to 20 liters, but is usually about 18 liters. Access to the water by a user is gained by manually actuating the front nozzle closed by a valve. When empty, this water bottle is removed and replace by second filled up water bottle.
Usually, the water filled inside these water bottles is pure spring water, or "filtered" water obtained usually under distillation or reverse osmosis processes.
Also, many of these fresh water dispensers have an internal refrigeration system connected to an electrical plug outlet, for maintaining the water at the temperature cooler than that of the room in which the dispenser is located, for convenience of the user.
Although the bacteria count of the so-called "pure" spring water is usually very low at the beginning, it will progressively increase due to favorable temperature and humidity levels. Moreover, contaminants in particular at the faucet outlet end, or at the spout inlet end of the water bottle, will also progressively increase the microbial count in the water conduits.
It is recognized that operating a water refrigerant system inside the dispenser apparatus will slow this contamination process, but will not prevent it, since at lower temperature settings (e.g., 10.degree. Celsius but obviously above freezing point), the microbial activity is slowed down but not stopped.
For the maintenance of water dispensers, it is recommended by health officials to periodically (i.e. once every two months) clean the internal parts thereof with a cleaning solution that will dissolve scale and eliminate pathogenic micro-organisms, including algae, lime, mould and fungus. The goal is to maintain the bacteria count of the water in the dispenser to a negligible value. Inappropriate cleaning compounds for water cooler dispensers include:
vinegar, being a good descaler but a poor disinfectant and generating a strong after-taste smell; PA0 sodium bicarbonate, not being a good descaler and being still less effective for disinfection; PA0 Javel water, being a good disinfectant but very poor descaler and also undesirably corrosive for the dispenser parts and ground carpets and user's clothes, as well as generating bad after-taste to the drinking water; and PA0 hydrochloric acid or phosphoric acid, since they do damage dispenser parts, and although good descalers, they are not good disinfectants. PA0 a) propylene glycol (or other glycol ether compounds), as a solvent ingredient thereof, and PA0 b) alkyl dimethyl benzyl ammonium chloride, as quaternary ammonium compound component thereof, for anti-microbial activity. PA0 a) citric acid (as part of an organic carboxylic acid); PA0 b) a thickener compound, i.e. either alkyl alcohol ether sulfates, amphoteric or nonionic surfactants, or amine oxides; PA0 b) a quaternary ammonium salt; and PA0 c) a deodorant perfume. PA0 a) an ammonium quaternary, in particular N'alkyl dimethyl Benzyl Ammonium Chloride, and preferably within the range of 0.08 to 0.1% by weight; PA0 b) an organic acid, (food grade), particularly a selection among citric acid, gluconic acid or hydroxy acetic acid, but most preferably citric acid, preferably within the range of 12 to 20% (most preferably about 20%); PA0 c) propylene glycol (food grade), preferably within the range of 2 to 10% (most preferably about 4%) ; and PA0 d) an alkaline base, preferably sodium hydroxide (food grade), in sufficient quantity to neutralize the solution to a pH range preferably between 2.6 and 4.5. PA0 a) removing the empty overhead water bottle; PA0 b) partially emptying the water reservoir, while still leaving a small body of water at the bottom of the water reservoir, wherein the water conduit network remains submerged; PA0 c) pour said cleaning compound onto the interior wall of the water reservoir, above water line of the remaining said body of water; PA0 d) with a sponge, spreading the cleaning compound against the interior wall of the water reservoir and scrubbing same therealong; PA0 e) leaving to stand the water dispenser for a period of time sufficient for the cleaning compound to reach out and penetrate the microbial and scale material; PA0 f) open the faucets to release the body of water and cleaning compound dissolved therein; PA0 g) unscrew the faucets and spray the cleaning compound into the water conduit network; PA0 h) with a tubular brush, brush the water conduit network and faucets; PA0 i) screw the faucets back in place and rinse with potable water; and PA0 j) install a filled up fresh water bottle, preliminary disinfected on his top surface with the cleaning compound.
U.S. Pat. No. 5,454,984 issued in October 1995 to Reckitt & Colman Inc., Discloses a cleaning composition for cleaning hard surfaces and including the Combinaton of two ingredients:
U.S. Pat. No. 4,891,150 issued in January 1990 to the German Corporation Joh. A Benckiser, discloses a cleaning compound directed at a cleansing and descaling compound, including the combination of four ingredients:
It is noted that the Benckiser patent stresses that the purpose of the thickening agent is for thickening the citric acid for enabling more thorough use thereof in sanitary cleansing applications. However, it will be recognized by those skilled in the art that this thickening of the cleaning solution for improving the descaling efficiency with citric acid, does unfortunately limit the maximum value of citric acid concentration by weight of total solution, to less than or equal to 10%. In the Benckiser patent, it is critical to thicken the descaling cleaning solution having citric acid, to obtain efficient removal of lime, scale, and rust.
U.S. Pat. No. 4,199,469 issued in 1980 to the German business concern Feldmann Chemie, discloses a compound and a method for cleaning water dispensers. The compound also has citric acid and alkyl dimethyl benzyl ammonium chloride as a quaternary ammonium, as well as an isopropyl alcohol. However, the phosphoric acid renders same non-biodegradable.
U.S. Pat. No. 5,492,629 issued in February 1996 to H E R C Products Inc., discloses a method of cleaning scale in water, including a quaternary ammonium compound having a hydrochloric acid selected in particular from the group comprising hydroxyacetic acid, citric acid, and gluconic acid.
These various above noted sanitary cleaning compound are not satisfactory in particular because they need the use of gloves being strongly corrosive or they need the use of mask because of their vapors.
They are also damageable to the environmental surfaces for example; clothes, carpets and floors. Particularly U.S. Pat. No. 4,199,469 and U.S. Pat. No. 5,492,629.
Others types of patent particularly like U.S. Pat. No. 5,454,984 will be ineffective in removing scale being simple hard surface disinfectant.
Other known cleaning compound limited to low concentration of acid like U.S. Pat. No. 4,891,150 tend to be active on the external surfaces of the dispenser parts. They are thick gel and dissolve very slowly and drop at the bottom of the inner reservoirs where they clog the entry's of conduits interfering with the cleaning process especially in aqueous systems. Also they tend not to be fully effective in seeping trough and dissolving thick scale deposits in the water conduits and inner reservoir of water dispensers particularly when the effective clean up intervals are much longer than recommended; say e.g. six months instead of the recommended intervals of two months. Moreover, these prior art cleaning solution usually need to be apply on dry surface. This will oblige that the system must first be completely purge of its water before clean-up is started and the cleaning solution can be used. They also produced high volume of foam and oblige to a long period of rinsing to eliminate the foam.; this is tedious and time consuming.
It can be readily understood even by the layman, that such cleaning process is tedious and much time-consuming. This tediousness could at least partially explain why so few water dispenser operators do in fact conform to the recommended two-months clean-up intervals. It is noted that in Canada, studies have shown that, often unbeknownst to the water dispenser operator themselves, up to a third of all water dispensers with coolers were contaminated with algae and scale concealed inside the system, due to poor maintenance. Also, one must remember that if the water dispenser is not thoroughly cleaned at each recommended interval, re-contamination of the water by the unremoved remaining microbes will rapidly occur as if no cleaning had ever happened.